<template>
    <div @click="generateCode" class="dzs-code-canvans-box">
        <canvas id="dzs-code-canvans" ref="dzs_code_canvans" class="dzs-code-canvans">您的浏览器不支持canvas</canvas>
    </div>
</template>
<script setup lang="ts">
import { onMounted, ref , defineExpose } from 'vue';
const props = defineProps({
    codeArr: {
        type: Array,
        default: () => {
            return []
        }
    },
    value: {
        type: String,
        default: () => {
            return ""
        }
    },
    uppercase: {
        type: Boolean,
        default: () => {
            return false
        }
    },
})
const emit = defineEmits(["update:value"]);
const dzs_code_canvans = ref<HTMLCanvasElement>();
const code_show = ref("");

onMounted(() => {
    generateCode()
})

const generateCode = () => {
    if (props.codeArr.length && props.codeArr.length < 4) {
        console.warn("codeArr.length Less than 4")
    }
    let show_num: Array<string> = [];
    let canvas_width = dzs_code_canvans.value?.width || 200;
    let canvas_height = dzs_code_canvans.value?.height || 100;
    let canvas: any = dzs_code_canvans.value; //获取到canvas的对象
    let context = canvas?.getContext("2d"); //获取到canvas画图的环境
    canvas.width = canvas_width;
    canvas.height = canvas_height;
    let sCode =
        "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
    let aCode: Array<any> = sCode.split(",");
    if (props.codeArr.length && props.codeArr.length > 4) {
        aCode = props.codeArr;
    }
    let aLength = aCode.length; //获取到数组的长度
    for (let i = 0; i < 4; i++) {
        //这里的for循环可以控制验证码位数（如果想显示6位数，4改成6即可）
        let j = Math.floor(Math.random() * aLength); //获取到随机的索引值
        // let deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
        let deg = Math.random() - 0.5; //产生一个随机弧度
        let txt = aCode[j]; //得到随机的一个内容
        show_num[i] = txt;
        let x = 10 + i * 70; //文字在canvas上的x坐标
        let y = 100 + Math.random() * 20; //文字在canvas上的y坐标
        context.font = "bold 63px 微软雅黑";
        context.translate(x, y);
        context.rotate(deg);
        context.fillStyle = randomColor();
        context.fillText(txt, 0, 0);
        context.rotate(-deg);
        context.translate(-x, -y);
    }

    code_show.value = show_num.join("");
    if (props.uppercase) {
        code_show.value = code_show.value.toLocaleUpperCase();
    }
    emit("update:value", code_show.value);
    for (let i = 0; i <= 5; i++) {
        //验证码上显示线条
        context.strokeStyle = randomColor();
        context.beginPath();
        context.moveTo(
            Math.random() * canvas_width,
            Math.random() * canvas_height
        );
        context.lineTo(
            Math.random() * canvas_width,
            Math.random() * canvas_height
        );
        context.stroke();
    }
    for (let i = 0; i <= 30; i++) {
        //验证码上显示小点
        context.strokeStyle = randomColor();
        context.beginPath();
        let x = Math.random() * canvas_width;
        let y = Math.random() * canvas_height;
        context.moveTo(x, y);
        context.lineTo(x + 1, y + 1);
        context.stroke();
    }
}

const randomColor = () => {
    let r = Math.floor(Math.random() * 256);
    let g = Math.floor(Math.random() * 256);
    let b = Math.floor(Math.random() * 256);
    return "rgb(" + r + "," + g + "," + b + ")";
}

defineExpose({
    generateCode
})
</script>
<style lang="scss" scoped>
.dzs-code-canvans-box {
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.dzs-code-canvans {
    width: 100%;
    height: 100%;
}
</style>